Power Cables Damaged by Heat. Canada.

I thought loading beyond prudent design limits was normal practice

I think you will find in the case of DNOs and similar, that this is better described as  case of knowing quite well how much slack there is in the original design, or if you prefer, knowing what the assumptions were behind the headline ‘cable ratings’ including  how long things really take to get hot, and the degree  premature ageing from various degrees of running  over temperature, and then a cost benefit analysis.

It really is perfectly OK to load things to 200% of the steady state  rating so long as you do not do it for very long and co-ordinate protection to match.

The hot and cold weather de-ratings is a very good example of this.

The problem is that you cannot play the same trick for overloads due to  aircon in the summer.

Mike.

I thought loading beyond prudent design limits was normal practice

I think you will find in the case of DNOs and similar, that this is better described as  case of knowing quite well how much slack there is in the original design, or if you prefer, knowing what the assumptions were behind the headline ‘cable ratings’ including  how long things really take to get hot, and the degree  premature ageing from various degrees of running  over temperature, and then a cost benefit analysis.

It really is perfectly OK to load things to 200% of the steady state  rating so long as you do not do it for very long and co-ordinate protection to match.

The hot and cold weather de-ratings is a very good example of this.

The problem is that you cannot play the same trick for overloads due to  aircon in the summer.

Mike.